Bj?rn wrote:
It does not matter if you do not find it usable, as
long as it IS the
traditional definition.
The PDP 10 came long after it had been established.
The PDP-10 uses the PDP-6 architecture, which offered variable-sized bytes
when it was designed in 1963. I do not think that any fixed byte size
was firmly established at that time; in fact, available evidence suggest
that a variable byte size was prevalent at the time. Even by the time
of the first PDP-10 introduction in 1968, the size of the byte had not
been standardized industry-wide, although it was moving in that
direction. Thus the PDP-10, far from contradicting a traditional
definition of byte, was in fact perpetuating the traditional definition.
The first computer to use bytes with that name was the IBM 7030 Data
Processing System (Stretch), which was designed from about 1957 to 1961
and introduced in 1961. Stretch used instructions that could address
variable-sized fields that were subdivided into bytes of from 1 to 8
bits, though they sometimes referred to an entire field longer than
8 bits as a byte.
IBM didn't standardize on an 8-bit byte until the introduction of
the System/360 in 1964, and I'm not aware of any other vendors having
standardized on 8 bit bytes before then. In fact, the PDP-6 is the
only non-IBM machine from 1964 or earlier for which I've seen the
manufacturer reference bytes at all.
Eric
References:
PDP-6 Handbook, Digital Equipment Corporation, 1964
http://bitsavers.org/pdf/dec/pdp6/F-65_PDP-6_Handbook_Aug64.pdf
Planning a Computer System, ed. Werner Buchholz, McGraw-Hill, 1962
http://ed-thelen.org/comp-hist/IBM-7030-Planning-McJones.pdf